The structural dynamics of polymer chains makes it difficult to describe the kinetics of the formation of loops and hairpins in examples such as nucleic acids and polypeptides. However, a team at the Laboratoire de Physique Théorique de la Matière Condensée in Paris, France, have introduced a new analytical approach which they say allows them to calculate the mean reaction time of polymer reactions. The work overturns the classical Markovian theory on such processes.

Their statistical approach demonstrates that conformations can be extended cutting the reaction times from monomer to polymer predicted by the classical approach to polymer kinetics. Loop and hairpin formation are two crucial processes in the regulation of gene expression, in protein folding and misfolding and so important to genetics as well as several areas of biomedical research in which protein folding goes awry.

• Non-Markovian polymer reaction kinetics,
  T. Guérin, O. Bénichou, R. Voituriez
  Nature Chem. 2012.
  DOI: 10.1038/nchem.1378